BACKGROUND Indication of oral appliances for the treatment of an obstructive sleep apnea (OSA) includes both patients with primary snoring and mild OSA, as well as patients with moderate to severe OSA who refuse other treatment or in whom such treatment failed. The aim of this study was to verify the effectiveness of current OSA treatment by objective measurements, and to assess by means of a questionnaire patients' satisfaction with oral appliances manufactured in our laboratory. MATERIAL AND METHODS The study enrolled 58 adult patients (40 men, 18 women) with mean age of 50.5 years; most were overweight or had class I obesity; mean baseline apnea-hypopnea index (AHI) value prior to the beginning of treatment was 31.3, range 0.6-71. RESULTS Average AHI reduction in the entire group was 10.4; 31% of patients experienced AHI reduction by at least 50%. Significant AHI reduction was proven when using the appliance. Appliances affect the reduction of AHI and patients tolerate the appliances well. CONCLUSIONS Oral appliances complement positive-pressure treatment and do not interfere with it in any way. Craniometric parameters seem to be applicable as predictors of success or failure of appliance treatment.